As illustrated above, an isolated sequence of three verbs is called
a fork; its monadic and dyadic cases are defined by:

g
/ \
f h
| |
y y

g
/ \
f h
/ \ / \
x y x y

The diagrams above provide visual images of the fork.

Before reading the notes at the right (and by using the facts
that %: denotes the root function and ] denotes
the identity function), try to state in English the significance
of each of the following sentences: